Known power window lift actuators may be configured with a single stage, single start worm and helical gear to affect window glass movement. These actuators may be designed with a low efficiency worm in conjunction with a large motor. The gear train may provide sufficient mechanical advantage to drive the window glass.
It is beneficial for the same gear train to provide an anti-back drive function to resist forced entry in to the vehicle. Balancing the back-drive may be a crucial element in the design. Hence the actuator may not be designed according to the maximum efficiency of the system. A large motor may be used to overcome the system inefficiency as well as to provide power to drive the window lift actuator. As a result, current draw for each actuator may be very high.
Furthermore, since the gear train has to withstand forced entry, the gear teeth should be designed to withstand such loading requirement. The gear teeth are also constantly being loaded against the window seal when window is closed in the non-operating state. The gear train, therefore, is highly susceptible to creeping, which could affect the life and performance of the window lift actuator.
There is, therefore, a need for a window lift actuator configuration that provides appropriate back-drive resistance in a reliable and cost-effective manner.